I'm really starting to feel like the lack of any SF3 characters announced so far is because Capcom's being coy about exactly when this game is meant to take place, relative to SF3/3S. It's obviously after SFIV, since we have visibly older Ken and Bison, and the hints of Illuminati dealings with Nash's head-gem and Necalli's tomb show that the lore of SF3, such as it is, is not being wholesale forgotten or retconned. What we don't yet know is whether this is supposed to occur between 4 and 3, or after 3 entirely, and my bet is that any SF3 returner that they show off (assuming there's at least one in the game) will immediately prove SFV's place, which they don't seem to want to do yet.
If "Eisbahn" really were a slightly-older Remy who now has an ice motif, well, I'd be up for it, but it would also force the game to take place after SF3, which currently feels a little weird given the huge number of returning SF2/4/A folks. 5 being the "Fall of Shadaloo/Rise of Illuminati" bridge-piece makes a bit more sense given who we already have, but it would also make the storylines of a few of the SF3 characters a bit awkward.
...Then again we already had folks like Ibuki and Dudley in SFIV when they had no real storyline reasons either, so fuggit. Gimme Alex/Q/Remy/Makoto, I'm sure they'd find some way to tie someone in.